Systematic relationships among southwestern subspecies of least chipmunks were reassessed using pelage color, morphologic criteria (crania and bacula), and protein electrophoresis. These data were analyzed phenetically and cladistically. A general cladogram derived from the analysis of all characters simultaneously produced the best representation of geographic variation within Tamias minimus. Groupings derived from this analysis are not congruent with current taxonomy. Genetic differentiation of the most isolated taxa is consistent with current geography and distance from the inferred ancestral source as predicted by vicariant biogeographic theory. Subspecific designations based on phenetic and cladistic analyses of pelage, morphologic, and genic data support retention of T. m. arizonensis as a distinct subspecies. Further, the relictual population of T. minimus from Sierra Blanca Peak, New Mexico, is shown to be more aligned with T. m. atristriatus from the Sacramento Mountains, New Mexico, than with populations ofT. m. operarius from more northern localities in the southern Rocky Mountains. Finally, a new subspecies of least chipmunk from the Chuska Mountains, Arizona and New Mexico, is described.
Sullivan, Robert Miles and Karen E. Petersen. "Systematics of Southwestern Populations of Least Chipmunks (Tamias minimus) Reexamined: A Synthetic Approach." (1988). http://digitalrepository.unm.edu/occasionalpapers/10